Staple pullers of various shapes and functional designs have been well known for many years. The most popular type of staple puller currently in common office use comprises a pair of hinged jaws which engage the staple from opposite sides and which wedge the staple upwardly from the paper. Another type of staple puller which is well known is a wedge shaped member which is inserted under the staple and pushed forward, forcing the staple out from the paper.
Various examples of such staple pullers are found in the patent literature. For example, Cochran, U.S. Pat. No. 910,173, shows a device having a linearly aligned handle and shank portion which terminates in a narrow inclined tip which is placed beneath the staple and which removes the staple by a lifting cam action actuated by pressing downwardly on the handle. This device tends to bend the staples in the middle to form an apex as they are removed, thereby precluding subsequent reuse. Goessel, U.S. Pat. No. 2,400,988, shows a linear device having two outwardly and upwardly extending flanges at the tip which act as wedges to lift the staple from the paper. A pair of horizontal slots in the flanges retain the staple as it is lifted from the paper. This device has a flat base which slides along the upper edge of the paper until the staple is caught in the slots.
Staple removers having wedge shaped operating surfaces are disclosed in Palmer, U.S. Pat. No. 2,375,942, and Viel, U.S. Pat. No. 3,625,482. Palmer shows a straight staple puller having a thin blade with a pair of wedges on each side of the blade and increasing in thickness towards the rear of the blade. The Viel patent also shows a wedge-shaped blade having a flat bottom similar to the Palmer device, except that the handle is a hollow receptacle which automatically receives detached staples.
All of the devices of the prior art are particularly designed to remove staples from multiple sheets of paper or from light fabric, but are not designed for heavy duty use such as on staples normally used to close packing cartons. These staples are much larger and more rigid than small paper staples, typically being about 21/2" long, 1/8" wide, and 1/32" thick. The force needed to remove these staples from packing cartons by a wedge or camming type action is much greater than that required to remove paper staples; accordingly, it has been found that the design parameters useful for paper staples do not apply to a device for removing carton staples. Because the force required to remove the staples is quite large, the normal hammertype grip shown in the devices of the art is not practical. It has been found that the user's hand slides forward and may slip, causing the possibility of injury on any sharp or projecting surfaces from the device. In addition, it is found that proper leverage to remove the staple cannot be obtained with this type of grip. Also, friction created between the carton surface and the staple puller, and between the staple and the staple puller, become very important forces to overcome when removing heavy-duty industrial staples.
Accordingly, it is an object of the invention to provide a relatively inexpensive, easy to manufacture, and simple apparatus to remove staples from cartons. It is another object of the invention to provide a device for removing staples from cartons which does not deform the staples, thereby permitting their reinsertion into the carton. It is yet another object of the invention to provide a staple puller having a blade with a cross-sectional design which minimizes frictional contact with surfaces contacting the blade. It is a further object of the invention to provide a carton staple puller which is completely safe, leaving no possibility for a staple to fly off and injure the user, and having no sharp edges. These and other objects are provided by the staple remover of the invention, a specific preferred embodiment of which is disclosed in detail herein.